Typewriting machine



Jan. 2, 1934. J. L. PETz TYPEWRITING MACHINE Filed May 23, 1931 f 1 INVENTOR ATroRNEY Patented Jan. 2, 1934 1,942,3@5 TYPIEITING MACHINE .reim L. Petz, Rochester, N. y., assignerte meetromatic Typewriters. llnc., Rochester, N. Y., a corporation of New York Application May 23, 1931. Serial No. 539,557

3 Claims. (Cl. l9Z,-'6)

This invention relates to improvements in typewriting machines, ,and the principal object of the invention is to provide simple and inexpensive means for impressing the Written characters in a Work sheet permanently, so that they cannot be erased or altered without destroying the material of the work sheet. i

Another object of the invention is to provideA an improved platen so constructed that portions of characters impressed on a work sheet arranged thereon Will be impressed in the material oi the work sheet.

Still another object of the invention is to provide an improved platen and cooperating type so constructed that impressions made thereby are lpermanently impressed in the material of the work sheet.

To these and other ends, the invention consists in the construction and arrangement of parts that will appear from the following description when read in conjunction with the accompanying y drawing, the novel features being pointed out in the claims at the end of the specification.

In the drawing: Fig. 1 is a transverse section through the platen of a typewriting machine constructed according to one embodiment of the invention;

Fig.. 2 is a fragmentary front elevation of the same; y

Fig. 3 is an enlarged side elevation of a type bar, part being broken away to conserve space;

Fig. 4 is a front elevation of the same;

Fig. 5 is a view similar to Fig. 3, illustrating a modified form of type. and

Fig. 6 is a front elevation of the same.

Referring particularly to Figs. l to 4 of the drawing, l is a platen preferably of the cylindrical type of usual construction, having an axle, a core of wood or other hard material, and a layer or outer covering 2 of resilient material, such as rubber or the like. The outer surface of the covering 2 is provided with longitudinally arranged flutes or projections 3 forming depressions between them. Said projections and depressions are comparatively small and are arranged substantially parallel with each other and terminate in bluntly sharp outer edges.

The types, such as shown at 4 in Figs. 3 and 4, are of usual construction, and are adapted to swing to and from striking engagement with the platen or vthe Work sheet thereon, as usual in this art. 'The relative sizes of the types and the projections Si are such that each of the typesengages a plurality of the projections when moved into engagement with the platen. When the type strikes the platen or the work sheet thereon, the

sheet engages the bluntly sharp edges of the projections 3, and the type cuts into the Work sheet and weakens it throughout the area engaged by the type. An impression made in this manner in a note, check or other document is permanent and. cannot be erased or altered without destroy# ing the material of which it is made.

Referring to Figs. 5 and 6. in which a modified form of type 5 is shown, this type comprises a plurality of elongated projections forming depressions between them and arranged to form a character. When such a type moves into engagement with the surface of a platen, such as illustrated, the projections 3, by reason of their resiliency, flex into registration with the depressions in the type. If a work sheet be arranged on the platen,v the character is impressed in the sheet in the form of alternate projections and depressions which cannot be eradicated or altered without destroying the material of the Work sheet. Such an arrangement is particularly valuable for writing checks, notes, or other documents which it isdesirable to protect against alteration, or for stenciling cards, or the like.

Although only two embodiments of the invention are shown and described herein, it will be understood that this application is intended to cover all-changes or modifications thereof which come within the spirit of the invention or scope of the following claims.

I claim: v

1. A platen for type writing machines comprising a core of hard material, a cover of relatively soft resilient material entirely surrounding the -core, said cover having aplurality of-parallel pressed in a work sheet when atype bar strikes.A

such work sheet against the platen.

2. A platen for typewriting machines comprising a core of hard material, and a cover of soft rubber vextending entirely around the core and having adplurality of parallel ridges and grooves in its'outer surface extending endwise of the platen, said ridges and grooves being lof substan tial size in cross-section so that they will cause a character to be impressed in a work sheet when Ia type bar strikes such work sheet against the a cover of relatively soft resilient material enand cooperating therewith to impress a. character in a.' work sheet by forcing portions o! the work sheet into several grooves between adjacent ridges on the platen.

JOHN L. PETZ.

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